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The Casio G-Shock GA-B2100CT-5A is a solar-powered, Bluetooth-linked analog-digital watch in the 2100 series. Its distinguishing details are a khaki-grey cloth band Casio describes as traceable organic TRUECOTTON, a band dye Casio says is extracted from echinacea, and a carbon/bio-based resin case and bezel. Casio calls the materials renewable, but the available product information does not quantify the watch’s lifecycle impact.
What the GA-B2100CT-5A offers
Casio lists the GA-B2100CT-5A as a G-SHOCK 2100 Series analog-digital model. It combines Tough Solar charging and Bluetooth smartphone linking with the octagonal 2100-series form and Carbon Core Guard construction. The specifications below are Casio’s, not independent test results.
| Specification | Casio listing |
|---|---|
| Case dimensions | 48.5 × 45.4 × 11.9 mm |
| Weight | 57 g |
| Case and bezel | Carbon/bio-based resin |
| Band | Cloth made of traceable organic TRUECOTTON |
| Construction and water resistance | Shock-resistant Carbon Core Guard; 200-meter water resistance |
| Glass and illumination | Mineral glass; double LED illumination |
| Time and timing functions | World time across 38 time zones, stopwatch, countdown timer and five daily alarms |
| Listed solar run time | Approximately seven months under normal use without light after charging, or 18 months stored in darkness with power saving enabled after a full charge |
Dimensions, weight, functions and power-run figures come from Casio’s U.S. product specification; they should be read as manufacturer claims rather than independently verified performance. Casio U.S. GA-B2100CT-5A specifications.
What Casio means by renewable materials
Case and bezel resin
Casio says key resin components use bio-based resin made from renewable organic resources and are expected to help curb CO2 emissions and reduce environmental impact. That is the manufacturer’s materials and benefit description; it is not a published lifecycle assessment quantifying this watch’s emissions or comparing it with a conventional-resin model.
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- Metal-clad daring meets sophisticated gleam in this Casio G-Shock that delivers Smartphone Link via Bluetooth(R) and Tough Solar charging system, all in a meticulously finished metal design with iconic octagonal bezel
- This model features a blue metallic vapor deposition dial that is complemented by a black band made of environmentally responsible bio-based resin
TRUECOTTON band and echinacea dye
Casio describes the band as traceable organic TRUECOTTON and says the cloth can be traced to its farm and spinning mill. The company also describes FOOD TEXTILE as a project that reuses food otherwise discarded to make dyes. For this watch’s khaki-grey band, Casio identifies echinacea as the dye source.
Casio says its natural dyes are made with “over 90% natural ingredients.” That figure refers to the ingredients in the dye description—not the total material content of the watch, a measured emissions reduction, or a lifecycle result. The product description does not establish an independent sourcing audit or quantify environmental outcomes. Casio Europe’s GA-B2100CT-5A materials description.
Rank #2
- Upgrade the retro look you love with the octagonal Casio G-Shock GA-2100 line, which inherits the design concept of the very first G-Shock, but now with Smartphone Link and Tough Solar power
- Bold in design, this model features a black carbon fiber-reinforced interior case and matching black resin band
How it compares with the GA-2100-5A
The related GA-2100-5A illustrates the practical differences between a conventional resin-band 2100 and this cloth-band solar model. The comparison is based on the two Casio product pages; it does not establish that the models are interchangeable or that their bands are compatible.
| Feature | GA-B2100CT-5A | GA-2100-5A |
|---|---|---|
| Power | Tough Solar; manufacturer lists approximately seven months of normal use without light after charging, or 18 months stored in darkness with power saving enabled after a full charge | Two SR726W cells; approximate three-year battery life |
| Connectivity | Bluetooth smartphone linking | Not stated on the cited product page |
| Band | Cloth made of traceable organic TRUECOTTON | Resin |
| Dimensions and weight | 48.5 × 45.4 × 11.9 mm; 57 g | Not stated on the cited product page |
| Materials and styling | Carbon/bio-based resin case and bezel; khaki-grey cloth band with echinacea-derived dye, according to Casio | Resin band; styling differs by model |
Sources: Casio GA-B2100CT-5A page and Casio GA-2100-5A page. Choose based on whether solar charging, Bluetooth, a cloth band and this particular material story matter more to you than the simpler battery-powered, resin-band configuration.
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Rank #3
- Tough Solar Power & Multi-Band 6 Atomic Timekeeping: Enjoy precise timekeeping with radio-controlled accuracy across six calibration signals worldwide, powered by Casio's efficient solar technology for continuous operation.
- Durable Stainless Steel Construction: Features a robust stainless steel band with a one-touch 3-fold clasp and a shock-resistant resin/stainless steel case, providing both durability and a sleek, sophisticated look.
- 200-Meter Water Resistance: Built to withstand extreme conditions, this watch is suitable for professional marine activities and serious surface water sports, offering water resistance up to 200 meters (660 feet).
- Versatile Timekeeping Functions: Equipped with world time across 31 time zones (48 cities), a 1/100-second stopwatch, 24-hour countdown timer, and 5 independent daily alarms (including a snooze alarm) to keep you on schedule.
- Electro-Luminescent Backlight with Full Auto EL: The blue-green EL backlight with afterglow ensures optimal readability in low-light conditions, automatically activating in dim environments for your convenience.
Who should consider this watch
- Consider it if you want the 2100-series analog-digital layout with Tough Solar, Bluetooth linking, 200-meter water resistance and a cloth band.
- Look closely at the band choice if you prefer resin; the GA-B2100CT-5A’s cloth construction is a defining difference from the GA-2100-5A.
- Treat the sustainability language as a materials description, not proof of a specific carbon saving or lower overall lifecycle impact.
- Check current local availability and price with a retailer, since the cited product information does not establish current stock or pricing.
A Casio Online Flagship regional listing gives January 2024 as the product launch date. That is the retailer listing’s date, not confirmation of a global release date. Casio Online Flagship listing.
Quick Recap
Best Value
- Bold, dynamic, electric - Tap into the energy of a G-SHOCK in striking black and electro green
- Featuring an LCD printed with touches of electro green, set against a bezel, band, and dial in G-SHOCK black, this is a fearless visual design that impresses and electrifies
- Case size (L? W? H): 48.5 ? 45.4 ? 11.9 mmCase and bezel material: Carbon / Bio-based resin Band: Bio-based resin bandConstruction: Shock Resistant; Carbon Core Guard structureWater resistance: 200-meter water resistanceTime adjustment - Bluetooth: Connects to a smartphone and automatically adjusts the timePower supply and battery life: Tough Solar (Solar powered)Smartphone Link feature: Mobile link (Wireless linking using Bluetooth(R))App connectivity feature: Auto time adjustment; Easy watch
Rank #4
- Solar-powered sport watch featuring atomic time keeping, world time in 48 cities, and EL backlight
- Features 1/100-second stopwatch, daily alarm with snooze, 12- and 24-hour formats, tide/moon graph, 31 time zones, and day/date/month calendars
- 50 mm resin case with mineral dial window
- Japanese quartz movement with digital display
- Resin band with buckle closure
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
